EP0994548B1 - Distance relay - Google Patents
Distance relay Download PDFInfo
- Publication number
- EP0994548B1 EP0994548B1 EP99118901A EP99118901A EP0994548B1 EP 0994548 B1 EP0994548 B1 EP 0994548B1 EP 99118901 A EP99118901 A EP 99118901A EP 99118901 A EP99118901 A EP 99118901A EP 0994548 B1 EP0994548 B1 EP 0994548B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- phase
- fault
- voltage
- phase voltage
- zis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/40—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to ratio of voltage and current
Definitions
- the invention relates to a distance relay equipment that aims to prevent unwanted operation due to over-reach.
- the impedance for the fault point is correctly found for the faulted phase, excluding the load current and fault point resistance etc.
- over-reach means that the operating range of a distance relay reaches out of the distance which shows a limit of operation or the range of an impedance.
- Under-reach means that a distance relay detects an internal fault in the operating range of the distance relay, excluding the output of operation.
- the OCR combines with a first-stage X1 of a distance relay in ab-phase.
- a circle shows characteristic of an mho relay element that finds a direction of fault
- X1 and X2 paralleling to an R axis shows reactance relay element that finds the distance where fault happens.
- X means "reactance”
- R means "resistance”.
- Fig.16 the operation of over-reach of a distance relay in ab-phase is locked when Zab is in a blinder operation zone.
- X means "reactance”
- R means "resistance”.
- blindder elements mean discriminating filter to protect the unwanted operation of the distance relay.
- the cooperation of the setting value such as to exclude the load impedance and setting with the object of preventing over-reach on fault occurrence can be difficult to operate, making it difficult to select an optimum setting value for use.
- Fig. 1 is a functional block diagram showing a first embodiment of a distance relay in connection with this invention.
- an operation judging unit 11 judges an operation of a short-circuit distance relay (ZIS) in an "ab" phase of a three-phase AC power system of phases a, b, c.
- ZIS short-circuit distance relay
- This ZIS-ab element operation decision unit 11 finds the fault impedance Zab from a phase-to-phase voltage Vab and a phase-to-phase current Iab, and makes a comparative decision with respect to a set impedance Xs.
- a judging signal is output from the ZIS-ab element operation judging unit 11.
- setting impedance means the limit of the distance relay of the operation
- fault impedance means the electrical distance to the fault location by calculating in the distance relay.
- operation decision units 12 and 13 judge operations of a ZIS-bc element, and a ZIS-ca element in a "bc" phase and a "ca” phase, respectively.
- the ZIS element operation judging units 12 and 13 find the fault impedance Zbc and Zca from phase-to-phase voltages Vbc and Vca and phase-to-phase currents Ibc and Ica and effect respective comparative judging with regard to a set impedance Xs.
- operation judging signals are output from ZIS-bc, ZIS-ca element operation judging units 12, 13.
- calculating units 14 to 16 are provided for the phase-to-phase voltage amplitudes in the ab-phase, bc-phase and ca-phase of the three-phase AC power system, according to a well-known way. These calculating units 14 to 16 calculate the amplitudes of Vab, Vbc, Vca, respectively.
- a minimum phase voltage selection unit 17 selects the minimum voltage phase (V ⁇ min) of a phase-to-phase voltage amplitudes found by calculating units 14 to 16.
- a faulted phase element output control unit 18 takes the AND of the minimum voltage phase (V ⁇ min) selected by this minimum phase voltage selection unit 17 and the operation phase judging signals of ZIS-ab, ZIS-bc, and ZIS-ca elements 11 to 13, and delivers an output signal if this AND condition is satisfied.
- an operation output control unit 19 judges whether or not two or more operated phases of ZIS elements are present.
- a final operation output control unit 20 outputs an OR signal of the output phases of the ZIS elements obtained by the output control unit 18 and the operation output control unit 19.
- time coordination is performed to match of the operating time between two or more relays and reset time to attain the desired result.
- the minimum phase voltage is selected by a minimum phase voltage selection unit 17.
- Fig. 2 is a flow chart showing the processing for selecting the minimum phase voltage performed by the minimum phase voltage selection unit 17.
- a comparison judging is performed of the relative values and absolute values of the amounts of change and sensitivity constant Vk (this value is determined by an applied system) of the three phase voltage amplitudes
- steps 201 to 203 representing the bc-phase judging will be explained. That is, as a comparative example, the bc-phase is set as the phase of lag.
- step 201 a level judging is performed in the phase of lead/ phase of lag with reference to the bc-phase.
- the sensitivity constant Vk on the right-hand side may be thought of as consisting of (mainly) the PT error: about 3%; the analogue input unit error: about 1%; and the calculation error of the amplitude: 1%, approximately, giving a total of 5% sensitivity taking the maximum values of these.
- the sensitivity constant Vk on the right-hand side may be thought of as consisting of (mainly) the PT error: about 3%; the analogue input unit error: about 1%; and the calculation error of the amplitude: 1%, approximately, giving a total of 5% sensitivity taking the maximum values of these.
- Vbc-phase the level of Vbc is determined in respective steps 202, 203.
- Vab of phase of lag is taken as the subject of comparison
- Vca of phase of lead is taken as the subject of comparison.
- step 202 the absolute value difference judging
- ⁇ Vk Due to the relationship of sound phase voltage (Vab, Vca) >> faulted phase voltage (Vbc), this magnitude relationship is found to be untrue, so processing advances to step 203, in which the level width of the sensitivity constant Vk is detected.
- step 203 the absolute value difference judging
- step 202 If, in step 202, the expression is found to be true or if in step 203 the expression is found to be false, this judging processing is bypassed.
- the output control unit 18 verifies coincidence of the operated phase of the ZIS element and the voltage minimum value.
- the output circuit is divided into two in the event of a two-phase (bc-phase) fault (an operation of ZIS element of one phase) and in the event of a three-phase fault (an operation of the ZIS elements of two or more phases).
- a minimum phase voltage detection processing 901 can be added in addition to a voltage difference judging processing 201 to 207. This performs minimum phase detection ⁇ min (
- ⁇ min
- the means of detection used for faulted phase discrimination for the result of operation judging of the ZIS element constituting the first stage of the short-circuit distance relay is to find the voltage minimum phase from the amplitude values of the phase-to-phase voltage amounts.
- each equation is judged with a fixed amplitude width.
- Vk the sensitivity constant value
- the minimum phase voltage is influenced by phase-to-phase variability of the main transformer on the system side or by errors produced by differences of individual items of hardware constituting the analogue input unit on the relay side.
- Vbc is selected with the conditions: Vab-Vbc > Vk true and
- the operation output of the ZIS element is regarded as valid only when the one phase selected as a voltage minimum value and the operation phase of the ZIS element are the same.
- the ZIS element of the sound phase (ab-phase) tends to be operated in the event of a two-phase fault because the Zab is in the operating area, if the voltage of this operated phase (ab-phase) is not selected as a minimum phase(i.e., it is not a faulted phase), the output of the ZIS element of the sound phase (ab-phase) is inhibited by AND function.
- the operation output of the ZIS elements is taken as valid, irrespective of the result of the minimum phase judging. That is, where, in the case of a three-phase fault, the ZIS elements of two or more phases are operated, the operation output of the ZIS elements is regarded as valid, irrespective of the voltage minimum phase selection condition.
- Fig. 6 (a) shows the relationship of a typical voltage and current vectors in the event of a short-circuit fault of bc-phase in reverse, even in the case of "Vbc ⁇ 0".
- the distance relay with impedance relay element has characteristic to look ahead and find forward fault. That is, the distance relay with impedance relay element can't find fault backward (equal to "in reverse"), correctly.
- the "polarity voltage Vp" refers to a quantity of electricity as the criteria of the direction judging to the fault location.
- Fig. 6 (b) shows the magnitude and phase of the voltage and current of the phase (ca-phase) of lag in the event of a fault of bc-phase in reverse, and the operation region of the direction discrimination element.
- the degree of margin in respect of in-operation is small. As the degree of margin is small, there is a possibility that the distance relay does malfunction by calculating error and external noise, etc.
- Fig. 7 shows the input waveforms and the relay operation output from an oscilloscope taken under these conditions.
- F1 and F3 are the impedance. That is, F1 is a location of the impedance before the fault happens, t1 is the time when F1 is calculated, F3 is a location of the impedance after the fault occurs in reverse, and t3 is the time when F3 is calculated.
- Fig. 7 shows that the ZIS'-ca-phase may be operated though ca-phase is the sound phase. But an incorrect operation at the final-stage ZIS'-ca-phase can be detected because of the AND function, even though the ZIS'-ca-phase is operated by a calculating error or an external noise, etc.
- "Incorrect operation” means that the relay does not operate when it should not operate.
- Fig. 8 and Fig. 9 are functional block diagrams of the second and third embodiments of a distance relay in connection with the present invention in which such a judging system is adopted.
- the difference from Fig. 1 is that, as a ZIS element operation judging units 101 to 103, conversion is effected into a voltage amount by multiplying the current by a set impedance, the phase difference or absolute value difference with respect to the introduced voltage being calculated as an operating quantity and a restraint quantity, judging of operation in the internal fault within the transmission line protection zone being performed in accordance with the result of a magnitude comparison of these.
- operating quantity means a quantity of electricity which acts in a direction in which the relay operates.
- the “restraint quantity” means a quantity of electricity which acts in an opposite direction to the direction in which the relay operates.
- the minimum phase in the minimum phase voltage selection unit 17 is selected by the processing of Fig.2.
- the minimum phase in the minimum phase voltage selection unit 17 is selected by the processing of Fig.3.
- the same operations and benefits as in the case of Fig. 1 are of course obtained with these constructions.
- Fig.10 shows a functional block diagram illustrating a fourth embodiment of a distance relay in connection with this present invention.
- an operation judging unit 121 judges an a-phase ground fault distance relay (ZIG-a) element of a three-phase AC power system of phases a, b, c.
- ZIG-a ground fault distance relay
- the operation judging unit 121 finds the fault impedance Za from the a-phase voltage Va and a-phase current Ia and compares it with set impedance Xs.
- operation judging units 122 and 123 are related to the ZIG elements of the b-phase and c-phase, respectively.
- the operation judging units 122, 123 find the fault impedance Zb, Zc from the b-phase voltage Vb and b-phase current Ib and the c-phase voltage Vc and c-phase current Ic and compare these with set impedance Xs, and, if Zb, Zc are smaller, respectively, output operation judging signals from the ZIG-b element operation judging unit 122 and ZIG-c element operation judging unit 123.
- judging units 124 to 126 judge the operation of insufficient voltage relay (UV-a, UV-b, UV-c) elements to which are respectively input the respective phase voltages, and that the judging units 124 to 126 deliver output signals by being operated when the phase voltage amounts are smaller than a set voltage.
- insufficient voltage relay UV-a, UV-b, UV-c
- An output control unit 127 identifies whether or not two or more phases of the judging units 124 to 126 of UV-a, UV-b, UV-c elements are operated.
- the output control unit 127 delivers an output signal.
- an output control unit 128 locks the operation judging signal that is output from the operation judging units 121 to 123 of the ZIG elements of each phase when an output signal is output from the output control unit 127. Except for whether the calculation quantities are phase-to-phase quantities or quantities of the respective phases, the system for calculating the fault impedance Za to Zc by the operation judging units 121 to 123 of the ZIG elements of each phase is found in the same as in the case of Fig. 1.
- the judging units 124 to 126 of the UV element of each phase calculate the amplitudes from the voltages of each phase, and compare these with setting value Vset.
- Vset is decided by the system. If they are smaller than Vset, they output an operation signal.
- the judging units 124 to 126 of the UV elements of each phase are operated in response to the faulted phase.
- the judging signal of the operation judging units 121 to 123 of the ZIG element is locked by the output signal that is output to the final output control unit 128 from the output control unit 127. That is, output is provided for the ground fault distance relay ZIG of the ground faulted single phase only.
- the operating duty of the ground fault distance relay is concerned solely with the single-phase ground fault (faults involving two or more phases are within the range of protection of the ZIS operation) . And, it acts to prevent unwanted operation of the ZIG in faults involving two or more phases where there is a risk of over-reach.
- This discrimination between the single-phase ground faults and faults involving two or more phases is performed on the basis of the UV element operated phase. If the UV element of only one phase is operated, operation of the ZIG element is regarded as valid; if the UV elements of two or more phases are operated, operation of the ZIG element is regarded as invalid.
- ZIG operation is prioritized.
- an unwanted ZIG operation in the event of a fault on two or more phases can be prevented, so a stable response that is operated only by single-phase faults can be reliably anticipated.
- the UV element will be operated on both 1L and 2L and on both faulted a phase and faulted b phase.
- the UV element of two or more phases is thereby operated and, as a result, operation output of the faulted phase 1L ZIG-a element and 2L ZIG-b element, constituting the operating duty, is inhibited. Accordingly, faulted phase judging is performed using the operation result of the UV element in order to do operation response in the event of a single-phase ground fault only, which is the basic object of the ground fault distance relay.
- the operation judging is entrusted to the aforementioned ZIG elements.
- the operation elements can be divided between short-circuit/ground faults. That is, this makes it possible to achieve independence of the logic judging and to avoid unwanted operation of ZIG elements in the case of faults involving two or more phases.
- Fig. 12 is a functional block diagram illustrating a fifth embodiment of a distance relay in connection with the invention. Some parts which are the same as in Fig.10 are given the same reference symbols and further description is omitted, only the points of differences being discussed.
- Fig.12 the points of differences from Fig. 10 are that, instead of the UV element judging units 124 to 126, operation judging is respectively performed in respect of mho relay (Z3G) elements (mho characteristic), and the Z3G element judging units 131 to 133 are provided that are employed as third-stage zone outputs.
- Z3G element judging units 131 to 133 "Ms" means a setting value of an mho relay element. This setting value is equal to a diameter of a circle of the mho relay element. This definition applies to a Fig.14 mentioned later.
- this output control unit 127 identifies whether a single-phase fault or a fault involving two or more phases is in question and takes the output of the ZIG element as valid only in the event of single-phase operation of the Z3G element.
- judging could be performed by equivalently replacing the impedance by a voltage by converting from the current and a setting value to a voltage.
- Fig. 13 and Fig. 14, respectively, show functional block diagrams of sixth and seventh distance relays in connection with this invention, in which such a judging system is adopted.
- the differences between Fig. 13 and Fig.14 from Fig.10 and Fig.12, respectively, are that, as a ZIG element operation judging units 141 to 143, conversion is effected to a voltage amount by multiplying the current by a set impedance and the phase difference or absolute value difference with respect to the introduced voltage is taken as the operation quantity, employing a minimum phase voltage selection condition as restricting quantity.
- a minimum phase voltage condition is added to the operation judging of the short-circuit distance relay, or a single-phase operation judging of the short-circuit distance relay, or a single-phase operation condition of the UV elements or Z3G elements is added to a ground fault distance relay so unwanted operation due to over-reach of a sound phase element can be prevented, making it possible to operate stable operation correctly responding to the faulted phase only.
Description
- The invention relates to a distance relay equipment that aims to prevent unwanted operation due to over-reach.
- In general, for the measured value of fault impedance in a distance relay, the impedance for the fault point is correctly found for the faulted phase, excluding the load current and fault point resistance etc.
- However, as is well known, over-reach or under-reach of the set impedance occurs in respect of the other phases (phases associated with the faulted phase).
- Here, "over-reach" means that the operating range of a distance relay reaches out of the distance which shows a limit of operation or the range of an impedance.
- "Under-reach" means that a distance relay detects an internal fault in the operating range of the distance relay, excluding the output of operation.
- A typical example of this tendency is the over-reach of the phase of lead in a short-circuit distance relay (ZIS) element described at p252 - p254 of "Protective Relay Techniques, Chapter 3" published on April 15, 1981 by Tokyo Denki University Publications Office.
- Conventionally, as a countermeasure for such over-reach, as described in "Backup Protective Relay Systems" p. 41, Volume 37, No. 1, published on June 5, 1981 by Denki Kyodo Kenkyu (Electrical Joint Research), which discloses the features in the preamble of
claims 1 and 7, systems of preventing unwanted operation output of a ZIS element of phase of lead during occurrence of a fault, using the operating condition of an over current relay (OCR) shown in Fig. 15, or systems wherein the over-reach zone is restricted by a combination of blinder elements shown in Fig. 16 are widely employed. - In Fig. 15(a), (b), the OCR combines with a first-stage X1 of a distance relay in ab-phase.
- In Fig. 15(b), a circle shows characteristic of an mho relay element that finds a direction of fault, and X1 and X2 paralleling to an R axis shows reactance relay element that finds the distance where fault happens.
- Here, in Fig.15(b), X means "reactance", R means "resistance".
- Therefore, the operation of over-reach of a distance relay in ab-phase is locked by in-operation of OCR in a phase when a fault happens in bc-phase.
- In Fig.16, the operation of over-reach of a distance relay in ab-phase is locked when Zab is in a blinder operation zone. In Fig.16, X means "reactance", R means "resistance".
- Here, "blinder elements" mean discriminating filter to protect the unwanted operation of the distance relay.
- However, when the OCR operation condition is employed in combination with a ZIS element, there is the problem that the fault detection current sensitivity of the ZIS element depends on the magnitude of the load current.
- Specifically, in the case of a heavy load system, it is necessary to raise the operation sensitivity of the OCR setting to a level such that this is normally not operated.
- But, as a result, inevitably, the operation detection sensitivity of the ZIS element when a fault occurs is adversely affected. Namely, distinguishing the fault is adversely affected, making it difficult to distinguish the fault current and load.
- Also, in the case of a countermeasure using the blinder element, the cooperation of the setting value such as to exclude the load impedance and setting with the object of preventing over-reach on fault occurrence can be difficult to operate, making it difficult to select an optimum setting value for use.
- It is an object of the present invention to provide a distance relay of high reliability by adopting a principal that does not depend on the magnitude of the load current for preventing unwanted operation of a distance relay element due to over-reach.
- It is a further object of the present invention to provide a distance relay wherein special consideration of setting in use is unnecessary, and wherein high reliability is provided, unaffected by system conditions.
- These objects are achieved by the present invention as defined in
claims 1 and 7. - Further advantageous embodiments are defined in the dependent claims.
- A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained and better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
- Fig. 1 shows a functional block diagram of a first embodiment of a distance relay in connection with the present invention.
- Fig.2 shows a flow-chart of a first embodiment of a distance relay in connection with the present invention.
- Fig.3 shows a flow-chart in which minimum phase voltage detection processing is added to the processing for selection of a minimum phase voltage.
- Fig.4 shows a first-stage zone and the impedance seen by the short-circuit distance relay in the event of a fault in an adjacent zone.
- Fig.5 shows a first-stage zone and the impedance seen by the short-circuit distance relay in the event of a fault in the home zone.
- Fig.6(a) shows the voltage and current vectors before and after a more-distant bc-phase 2φS fault.
- Fig.6(b) shows the directional element operation tendency in the event of such a fault.
- Fig.7 shows an input waveform in the event of a simulated more-distant 2φS fault from the load current condition in the form of an oscilloscope waveform of the operation output.
- Fig.8 is a functional block diagram of a second embodiment of a distance relay in connection with the invention.
- Fig.9 is a functional block diagram of a third embodiment of a distance relay in connection with the invention.
- Fig. 10 is a functional block diagram of a fourth embodiment of a distance relay in connection with the invention.
- Fig.11 is a parallel two-circuit system diagram of a condition in which a single-line ground fault has occurred in different phases of the two circuits in a bus line voltage.
- Fig. 12 is a functional block diagram showing a fifth embodiment of a distance relay in connection with this invention.
- Fig.13 is a functional block diagram of a sixth embodiment of a distance relay according to the invention.
- Fig.14 is a functional block diagram of a sixth embodiment of a distance relay in connection with the invention.
- Figs. 15, 16 shows prior art examples.
- Embodiments of this invention are described below with reference to the drawings.
- Fig. 1 is a functional block diagram showing a first embodiment of a distance relay in connection with this invention.
- In Fig.1, an
operation judging unit 11 judges an operation of a short-circuit distance relay (ZIS) in an "ab" phase of a three-phase AC power system of phases a, b, c. - This ZIS-ab element
operation decision unit 11 finds the fault impedance Zab from a phase-to-phase voltage Vab and a phase-to-phase current Iab, and makes a comparative decision with respect to a set impedance Xs. - If the Zab is smaller, a judging signal is output from the ZIS-ab element
operation judging unit 11. - Here, "setting impedance" means the limit of the distance relay of the operation, "fault impedance" means the electrical distance to the fault location by calculating in the distance relay.
- Likewise,
operation decision units - The ZIS element
operation judging units - If Zbc, Zca are smaller, operation judging signals are output from ZIS-bc, ZIS-ca element
operation judging units - In the ZIS element
operation judging unit 11, "θ" means phase of Vab, Iab. (This definition applies to "θ" in Fig.10.) In the ZIS elementoperation judging unit 12, "θ" means phase of Vbc, Ibc. (This definition applies to "θ" in Fig.10.) In the ZIS elementoperation judging unit 13, "θ" means phase of Vca, Ica. (This definition applies to "θ" in Fig.10.) - Also, calculating
units 14 to 16 are provided for the phase-to-phase voltage amplitudes in the ab-phase, bc-phase and ca-phase of the three-phase AC power system, according to a well-known way. These calculatingunits 14 to 16 calculate the amplitudes of Vab, Vbc, Vca, respectively. - Further, a minimum phase
voltage selection unit 17 selects the minimum voltage phase (VΔmin) of a phase-to-phase voltage amplitudes found by calculatingunits 14 to 16. - A faulted phase element
output control unit 18 takes the AND of the minimum voltage phase (VΔmin) selected by this minimum phasevoltage selection unit 17 and the operation phase judging signals of ZIS-ab, ZIS-bc, and ZIS-ca elements 11 to 13, and delivers an output signal if this AND condition is satisfied. - Also, an operation
output control unit 19 judges whether or not two or more operated phases of ZIS elements are present. - A final operation
output control unit 20 outputs an OR signal of the output phases of the ZIS elements obtained by theoutput control unit 18 and the operationoutput control unit 19. - The method of calculating the fault impedance Zab, Zbc, and Zca by means of
operation judging units 11 to 13 of a short-circuit distance relay is not the main essence of this invention, so a detailed description thereof is omitted. - However, the method of, for example, Japanese Patent Publication No. H.3-20969 and pp.51 - 64, pp.119 - 127 of "Protective Relay Engineering " published on July 21, 1981 by Denki Gattkai discloses an the differential equation principle.
- Next, the operation of operation output judging logic of the short-circuit distance relay using a minimum value of the voltage amplitude will be described.
- Since AND processing of the amplitude value |VΔ| (equal to |Vab|, | Vbc| and |Vca|) of the phase-to-phase voltages by the calculating
units 14 to 16 with the operated phase of the short-circuit distance relay is performed after selection of the minimum phase voltage (VΔmin), as will be described, for timing consideration, the amplitude value calculation by the calculatingunits 14 to 16 must be performed with a higher-speed calculation than the operation judging of theoperation judging units 11 to 13. - Here, "time coordination" is performed to match of the operating time between two or more relays and reset time to attain the desired result.
- Of the three phase amplitudes - |VΔ| found by these calculating
units 14 to 16, the minimum phase voltage is selected by a minimum phasevoltage selection unit 17. - Fig. 2 is a flow chart showing the processing for selecting the minimum phase voltage performed by the minimum phase
voltage selection unit 17. - In
steps 201 to 207 in Fig. 2, a comparison judging is performed of the relative values and absolute values of the amounts of change and sensitivity constant Vk ( this value is determined by an applied system) of the three phase voltage amplitudes |Vab|, |Vbc|, and |Vca| found by the calculatingunits 14 to 16, respectively. - Here, steps 201 to 203 representing the bc-phase judging will be explained. That is, as a comparative example, the bc-phase is set as the phase of lag.
- Firstly, in
step 201, a level judging is performed in the phase of lead/ phase of lag with reference to the bc-phase. - The judging of the absolute value of the difference | |Vab|-|Vca| | < Vk of the corresponding voltages of the sound phases (which are practically in equal relationship) gives the result that this magnitude comparison is true, so processing shifts to the
next step 202. - The sensitivity constant Vk on the right-hand side may be thought of as consisting of (mainly) the PT error: about 3%; the analogue input unit error: about 1%; and the calculation error of the amplitude: 1%, approximately, giving a total of 5% sensitivity taking the maximum values of these. Thus, about 0.05 pu (110 V × 5% = 5.5 V) is available.
- Next, turning to the bc-phase, the level of Vbc is determined in
respective steps - In
step 202, the absolute value difference judging | |Vab|-|Vbc| | < Vk is performed. Due to the relationship of sound phase voltage (Vab, Vca) >> faulted phase voltage (Vbc), this magnitude relationship is found to be untrue, so processing advances to step 203, in which the level width of the sensitivity constant Vk is detected. - In
step 203, the absolute value difference judging |Vab| - |Vbc| > Vk succeeds, so instep 209 the bc-phase is identified. - If, in
step 202, the expression is found to be true or if instep 203 the expression is found to be false, this judging processing is bypassed. - The same processing is subsequently carried out for the other phases.
- Next, the
output control unit 18 verifies coincidence of the operated phase of the ZIS element and the voltage minimum value. - Even if, exceptionally, it should happen that there is a fault in two phases (bc-phase) in the ZIS
element judging units 11 to 13, due to the AND condition of theoutput control unit 18, unwanted operation can be prevented. - As above, since, in a three-phase fault, the sound phase voltage disappears and the minimum phase voltage disappears, with the result that the judging made by the minimum phase
voltage selection unit 17 becomes invalid, if the operated phase of the ZIS element is established for two or more phases by theoutput control unit 19 of the operation phase, the operation output is given priority by the OR gate. - As a result, the output circuit is divided into two in the event of a two-phase (bc-phase) fault (an operation of ZIS element of one phase) and in the event of a three-phase fault (an operation of the ZIS elements of two or more phases).
- And, the OR of these two is taken by the
output control unit 20 of the final operation. Therefore, a stable operation in the event of a three phase fault can be achieved by combining this with the sound phase over-reach countermeasures for the case of a two-phase fault. - In the embodiment described above, the processing function of the minimum phase
voltage selection unit 17 was described with reference to the flow chart shown in Fig. 2. - However, as the processing function of the minimum phase
voltage selection unit 17, as shown in Fig. 3, a minimum phasevoltage detection processing 901 can be added in addition to a voltage difference judging processing 201 to 207. This performs minimum phase detection {min (|Vab|, |Vbc|, |Vca|) } as a backup to enable a minimum phase voltage to be obtained when none of thesteps voltage selection unit 17 also. - Next, the protective operation using the short-circuit distance relay constructed as above in the event of a system fault will be described.
- The means of detection used for faulted phase discrimination for the result of operation judging of the ZIS element constituting the first stage of the short-circuit distance relay is to find the voltage minimum phase from the amplitude values of the phase-to-phase voltage amounts. Here, each equation is judged with a fixed amplitude width.
|VΔ|: the difference value of the amplitudes
Vk : the sensitivity constant value - 1)
- 2)
- The effect of these amplitudes will now be described.
- If, when finding the minimum phase voltage, the comparison is effected purely in terms of an absolute value of the amplitude, the minimum phase voltage is influenced by phase-to-phase variability of the main transformer on the system side or by errors produced by differences of individual items of hardware constituting the analogue input unit on the relay side.
- To reduce these causes of error, a comparison of amplitudes is employed with a bandwidth based on a certain fixed value Vk. For example, in the case of selection of the bc-phase, Vbc is selected with the conditions: Vab-Vbc > Vk true and |Vab-Vbc| < Vk false.
- In this case, even considering a timing in which no minimum phase is selected from the difference calculation results in voltage change during a transient response period, if a function is provided for selecting a minimum phase voltage by reference to the absolute value base of the three-phase voltage amplitudes, one phase will definitely be selected.
- Next, the operation output of the ZIS element is regarded as valid only when the one phase selected as a voltage minimum value and the operation phase of the ZIS element are the same.
- This has the effect of preventing unwanted operations in the case of a fault between an adjacent zone as shown in Fig. 4, where the ZIS element of the sound phase (ab-phase) is a single-phase over-reach while the ZIS elements of the fault phase (bc-phase) and the sound phase (ca-phase) are not operated, resulting in an instantaneous operation of the first stage of the ZIS element.
- Specifically, although the ZIS element of the sound phase (ab-phase) tends to be operated in the event of a two-phase fault because the Zab is in the operating area, if the voltage of this operated phase (ab-phase) is not selected as a minimum phase(i.e., it is not a faulted phase), the output of the ZIS element of the sound phase (ab-phase) is inhibited by AND function.
- That is, the operation output of the ZIS element of the sound phase (ab-phase) is only regarded as valid if the ZIS element of the operated phase and the voltage minimum phase are the same. In contrast, in the event of a three-phase fault, no minimum phase of the phase-to-phase voltages exists, so reliable faulted phase detection is not possible.
- Consequently, in the event of a three-phase fault (i.e., where the ZIS elements of two or more phases are operated) , the operation output of the ZIS elements is taken as valid, irrespective of the result of the minimum phase judging. That is, where, in the case of a three-phase fault, the ZIS elements of two or more phases are operated, the operation output of the ZIS elements is regarded as valid, irrespective of the voltage minimum phase selection condition.
- As shown in Fig. 5, in the case where a ZIS element of a faulted phase (bc-phase) is operated by a two-phase fault in a home zone, and the ZIS element of the sound phase (ab-phase) is also operated because the Zab is in the operating area, there is a possibility that the sound phase (ab-phase) may deliver an operation output due to the two-phase operation of the aforesaid ZIS elements.
- But, since, in terms of the device system, a fault removal (three-phase trip) is performed by correct operation by OR function of the ZIS elements of the faulted phase (bc-phase) and the operated phase (ab-phase), there is no possibility of the protective function being impeded.
- Hereinabove, the validity of the sound phase over-reach countermeasures in the case of a fault in the adjacent zone, and countermeasures for the correct operation in the case of the home zone three-phase fault are described. Further, these also improve the direction discrimination performance in the case of reverse fault at even greater distance, by using the minimum phase voltage judging.
- The output inhibition effect and the phase of lag operation tendency in the case of heavy power flow are described below.
- In Figs.4 and 5, X means "reactance", R means "resistance".
- Fig. 6 (a) shows the relationship of a typical voltage and current vectors in the event of a short-circuit fault of bc-phase in reverse, even in the case of "Vbc ≒ 0".
- Here, the distance relay with impedance relay element has characteristic to look ahead and find forward fault. That is, the distance relay with impedance relay element can't find fault backward (equal to "in reverse"), correctly. To solve this problem, direction judging of the current is performed by means of the phase difference of the polarity voltage Vp and the IF (= IL - IF') obtained by superimposing the fault current IF on the load current IL prior to the fault.
- The "polarity voltage Vp" refers to a quantity of electricity as the criteria of the direction judging to the fault location.
-
- Fig. 6 (b) shows the magnitude and phase of the voltage and current of the phase (ca-phase) of lag in the event of a fault of bc-phase in reverse, and the operation region of the direction discrimination element.
- It can be seen that the degree of margin in respect of in-operation is small. As the degree of margin is small, there is a possibility that the distance relay does malfunction by calculating error and external noise, etc.
- In this connection, if the minimum phase detection condition as described above is added, Vca is not detected as the minimum phase, so the tendency of the ZIS-ca element to be operated can be avoided.
- Fig. 7 shows the input waveforms and the relay operation output from an oscilloscope taken under these conditions. Here, F1 and F3 are the impedance. That is, F1 is a location of the impedance before the fault happens, t1 is the time when F1 is calculated, F3 is a location of the impedance after the fault occurs in reverse, and t3 is the time when F3 is calculated.
- When a bc-phase fault occurs in reverse, waveforms of Ib, Ic, Vb and Vc abnormaly change from t1 to t3. That is, as the fault current is added to Ib and Ic, as a result, an amplitude of the waveforms of Ib and Ic get large between t1 and t3. And, likewise, an amplitude of the waveforms of Vb and Vc becomes small between t1 and t3 because the phase of Vb and Vc is reverse with respect to the phase of Va.
- Fig. 7 shows that the ZIS'-ca-phase may be operated though ca-phase is the sound phase. But an incorrect operation at the final-stage ZIS'-ca-phase can be detected because of the AND function, even though the ZIS'-ca-phase is operated by a calculating error or an external noise, etc. Here, "Incorrect operation" means that the relay does not operate when it should not operate.
- In the embodiment described above, a calculation system is described in which an operation judging by the distance relay is performed by directly calculating the impedance component.
- However, it would alternatively be possible to convert the impedance to a voltage from the current and the setting value, so that the impedance is equivalently replaced by the voltage. As the principle of this operation judging, for example, the phase difference judging system or absolute value comparison system described in "Protective Relay Engineering" published on July 20, 1981 by the Electrical Association of Japan, p.122 may be applied.
- Fig. 8 and Fig. 9 are functional block diagrams of the second and third embodiments of a distance relay in connection with the present invention in which such a judging system is adopted. The difference from Fig. 1 is that, as a ZIS element
operation judging units 101 to 103, conversion is effected into a voltage amount by multiplying the current by a set impedance, the phase difference or absolute value difference with respect to the introduced voltage being calculated as an operating quantity and a restraint quantity, judging of operation in the internal fault within the transmission line protection zone being performed in accordance with the result of a magnitude comparison of these. Here, "operating quantity" means a quantity of electricity which acts in a direction in which the relay operates. The "restraint quantity" means a quantity of electricity which acts in an opposite direction to the direction in which the relay operates. - Thus, in Fig. 8, the minimum phase in the minimum phase
voltage selection unit 17 is selected by the processing of Fig.2. - In Fig.9, the minimum phase in the minimum phase
voltage selection unit 17 is selected by the processing of Fig.3. The same operations and benefits as in the case of Fig. 1 are of course obtained with these constructions. - Fig.10 shows a functional block diagram illustrating a fourth embodiment of a distance relay in connection with this present invention. In Fig.10, an
operation judging unit 121 judges an a-phase ground fault distance relay (ZIG-a) element of a three-phase AC power system of phases a, b, c. - The
operation judging unit 121 finds the fault impedance Za from the a-phase voltage Va and a-phase current Ia and compares it with set impedance Xs. - If Za is smaller, an operation judging signal is output from the ZIG-a element
operation judging unit 121. - Likewise,
operation judging units - The
operation judging units operation judging unit 122 and ZIG-c elementoperation judging unit 123. - Also, judging
units 124 to 126 judge the operation of insufficient voltage relay (UV-a, UV-b, UV-c) elements to which are respectively input the respective phase voltages, and that the judgingunits 124 to 126 deliver output signals by being operated when the phase voltage amounts are smaller than a set voltage. - An
output control unit 127 identifies whether or not two or more phases of the judgingunits 124 to 126 of UV-a, UV-b, UV-c elements are operated. - If two or more phases are operated, the
output control unit 127 delivers an output signal. - As an example of a method for calculation done by judging
units 124 to 126 of UV-a, UV-b, UV-c elements, the method disclosed in Japanese Patent Publication No. H.3-20969( as differential equation principle) and pp.22 - 26, pp. 135 - 137 of "Protective Relay Engineering" published by Denki Gattkai can be used. - Furthermore, an
output control unit 128 locks the operation judging signal that is output from theoperation judging units 121 to 123 of the ZIG elements of each phase when an output signal is output from theoutput control unit 127. Except for whether the calculation quantities are phase-to-phase quantities or quantities of the respective phases, the system for calculating the fault impedance Za to Zc by theoperation judging units 121 to 123 of the ZIG elements of each phase is found in the same as in the case of Fig. 1. - A detailed description thereof is therefore omitted.
- Next, the operation of the output judging logic of the ground fault distance relay using the operation condition of the UV element will be described.
- The judging
units 124 to 126 of the UV element of each phase calculate the amplitudes from the voltages of each phase, and compare these with setting value Vset. Here, "Vset" is decided by the system. If they are smaller than Vset, they output an operation signal. - Also, the judging
units 124 to 126 of the UV elements of each phase are operated in response to the faulted phase. - In the event of a single-phase fault, only the single-phase corresponding to the fault is operated, and, in the event of a fault on two or more phases, a plurality of phases are operated. In regard to the output of the judging
units 124 to 126 of the UV element of each of these phases, identification of the operated phase is performed by theoutput control unit 127. - In the event of a fault on two or more phases, the judging signal of the
operation judging units 121 to 123 of the ZIG element is locked by the output signal that is output to the finaloutput control unit 128 from theoutput control unit 127. That is, output is provided for the ground fault distance relay ZIG of the ground faulted single phase only. - Next, the protective operation of the ground fault distance relay constructed as above in the event of a system fault will be described.
- The operating duty of the ground fault distance relay is concerned solely with the single-phase ground fault (faults involving two or more phases are within the range of protection of the ZIS operation) . And, it acts to prevent unwanted operation of the ZIG in faults involving two or more phases where there is a risk of over-reach.
- This discrimination between the single-phase ground faults and faults involving two or more phases is performed on the basis of the UV element operated phase. If the UV element of only one phase is operated, operation of the ZIG element is regarded as valid; if the UV elements of two or more phases are operated, operation of the ZIG element is regarded as invalid.
- In the event of a fault involving two or more phases, ZIG operation is prioritized. As a result, an unwanted ZIG operation in the event of a fault on two or more phases can be prevented, so a stable response that is operated only by single-phase faults can be reliably anticipated.
- Furthermore, considering the case where the application system is one in which voltage is taken from the bus by a parallel two-circuit line as shown in Fig. 11, in the case where multiple faults of different phases appear on both circuits, for example 1L: a-phase -1φG, 2L: b phase - 1φG faults, due to the effect of the bus voltage drop, the UV element will be operated on both 1L and 2L and on both faulted a phase and faulted b phase.
- The UV element of two or more phases is thereby operated and, as a result, operation output of the faulted
phase 1L ZIG-a element and 2L ZIG-b element, constituting the operating duty, is inhibited. Accordingly, faulted phase judging is performed using the operation result of the UV element in order to do operation response in the event of a single-phase ground fault only, which is the basic object of the ground fault distance relay. - In the event of UV operation on two or more phases, the operation judging is entrusted to the aforementioned ZIG elements. As a result, the operation elements can be divided between short-circuit/ground faults. That is, this makes it possible to achieve independence of the logic judging and to avoid unwanted operation of ZIG elements in the case of faults involving two or more phases.
- Therefore, stable operation in the event of a fault can be anticipated.
- Fig. 12 is a functional block diagram illustrating a fifth embodiment of a distance relay in connection with the invention. Some parts which are the same as in Fig.10 are given the same reference symbols and further description is omitted, only the points of differences being discussed.
- In Fig.12, the points of differences from Fig. 10 are that, instead of the UV
element judging units 124 to 126, operation judging is respectively performed in respect of mho relay (Z3G) elements (mho characteristic), and the Z3Gelement judging units 131 to 133 are provided that are employed as third-stage zone outputs. In the Z3Gelement judging units 131 to 133, "Ms" means a setting value of an mho relay element. This setting value is equal to a diameter of a circle of the mho relay element. This definition applies to a Fig.14 mentioned later. - When the operation judging signal of these Z3G
element judging units 131 to 133 is input tooutput control unit 127, thisoutput control unit 127 identifies whether a single-phase fault or a fault involving two or more phases is in question and takes the output of the ZIG element as valid only in the event of single-phase operation of the Z3G element. - This means that an extra relay element for output control of the ZIG element is unnecessary and this can be implemented by simple processing using only the first stage to the third stage elements constituted as an ordinary ground fault distance relay. The same action and benefits as in the case of the fourth embodiment can be obtained with this construction also.
- In the embodiments described above, a calculation system is described in which the impedance component is directly calculated in the operation judging of the distance relay.
- However, judging could be performed by equivalently replacing the impedance by a voltage by converting from the current and a setting value to a voltage.
- Fig. 13 and Fig. 14, respectively, show functional block diagrams of sixth and seventh distance relays in connection with this invention, in which such a judging system is adopted. The differences between Fig. 13 and Fig.14 from Fig.10 and Fig.12, respectively, are that, as a ZIG element
operation judging units 141 to 143, conversion is effected to a voltage amount by multiplying the current by a set impedance and the phase difference or absolute value difference with respect to the introduced voltage is taken as the operation quantity, employing a minimum phase voltage selection condition as restricting quantity. - The same benefits as in the fourth and fifth embodiments are of course thereby obtained. With the inventions described above, a minimum phase voltage condition is added to the operation judging of the short-circuit distance relay, or a single-phase operation judging of the short-circuit distance relay, or a single-phase operation condition of the UV elements or Z3G elements is added to a ground fault distance relay so unwanted operation due to over-reach of a sound phase element can be prevented, making it possible to operate stable operation correctly responding to the faulted phase only.
- Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Claims (11)
- A distance relay equipment for detecting a protective region having a fault, among a protective zone that includes a plurality of protective regions, based on a status of a power system, characterized by
an operation decision unit (11, 12, 13) having short-circuit fault distance relay elements that input respectively an electrical quantity from an AC power system of three phases a, b and c, the operation decision unit calculating a fault impedance (Zab, Zbc, Zca) from each of the electrical quantities to compare said fault impedance, which correspond to ab-phase, bc-phase and ca-phase, with a set impedance (Xs), to produce a judging signal of each ZIS (zone first for phase fault) element (ZIS element-ab, ZIS element-bc and ZIS element-ca), depending on the result of said comparison;
a calculating unit (14, 15, 16) for calculating a phase-to-phase voltage amplitude (|Vab|, |Vbc|, |Vca|) in said ab-phase, bc-phase and ca-phase ;
a minimum phase voltage selection unit (17) for selecting a minimum voltage phase (VΔmin) for the phase-to-phase voltage amplitudes (|Vab|, |Vbc|, |Vca|) determined by said calculating unit (14, 15, 16) ;
a fault phase element output unit (18) for having an AND function, which is set to each of the phases (ab-phase, bc-phase, ca-phase) of said minimum voltage phase (VΔmin) selected by said minimum phase voltage selection unit (17) and said judging signal (ZIS element-ab, ZIS element-bc and ZIS element-ca), and outputs an operation signal, to separate, the protective region having the fault, from the protective zone, of said ZIS element-ab, said ZIS element-bc and said ZIS element-ca, if said AND condition is satisfied; and
an operation output unit (19) for judging whether or not two or more operated phases of the ZIS elements are present, to output an operation signal of said ZIS elements to separate the protective region having the fault from the other protective zones. - A distance relay equipment according to claim 1, wherein said minimum phase voltage selection unit (17) comprises:a first unit for determining a first value equal to the absolute value of the difference between the absolute value of a first phase voltage and the absolute value of a second phase voltage;a second unit for determining a second value equal to the absolute value of the difference between the absolute value of a first phase voltage and the absolute value of a third phase voltage;a selection unit for selecting the first phase voltage ifi)the first and second values are greater than a predetermined threshold,ii)the absolute value of the difference between the absolute value of the thirdphase voltage and the absolute value of the second phase voltage is less than the predetermined threshold, andiii)the difference between the absolute value of the third phase voltage and the absolute value of the first phase voltage is greater than the predetermined threshold;the selection unit selecting the second phase voltage ifi)the first value is greater than the predetermined threshold,ii)the second value is less than the predetermined threshold, andiii)the difference between the absolute value of the first phase voltage and the absolute value of the second phase voltage is greater than the predetermined threshold; andthe selection unit selecting the second phase voltage ifi)the first value is less than the predetermined threshold,ii) the second value is greater than the predetermined threshold, andiii)the difference between the absolute value of the first phase voltage and the absolute value of the third phase voltage is greater than the predetermined threshold.
- A distance relay equipment according to claim 2, further comprising:a third unit for selecting the minimum voltage phase among said first phase voltage, said second phase voltage and said third phase voltage if said selection unit does not select one of the phase voltages.
- A distance relay equipment according to claim 2 or 3 wherein said predetermined threshold is about 0.05 pu.
- A distance relay equipment according to claim 1 wherein said operation decision unit (11, 12, 13) output a judging signal if the following equations are satisfied:
where Iab, Ibc and Ica are a phase-to-phase current;
where Vab, Vbc and Vca are a phase-to-phase voltage; and
where Xs is a setting impedance. - A distance relay equipment according to claim 1 wherein said operation decision unit (11, 12, 13) outputs a judging signal if the followings equations are satisfied:
- A distance relay equipment, for detecting a protective region having a fault, among a protective zone that includes a plurality of protective regions, based on status of a power system, characterized by
an operation decision unit (121, 122, 123) having ground fault distance relay elements that input respectively an electrical quantity from an AC power system of three phases a, b and c, calculating a fault impedance (Za, Zb, Zc) from each electrical quantity and compare said fault impedance with a set impedance (Xs) and that, making a judging signal of each ZIG (zone first for earth fault) element (ZIG element-a, ZIG element-b and ZIG element-c), depending on the result of said comparison;
a calculating unit (124, 125, 126) having an under-voltage relay element, outputting a judging signal if an absolute value of each phase voltage (|Va|, |Vb|, |Vc|) is larger than a prefixed value;
an output unit (127) identifying whether or not said judging signal outputted from said calculating unit (124, 125, 126) is present for two or more phases;
a final output unit (128), if said judging signal is present for two or more phases in said output unit, performing an output of an operation signal, to separate a protective region having fault from the protective zone, of all of said judging signal of said operation decision unit (121, 122, 123) to a non-operated side. - A distance relay equipment according to claim 7, wherein said calculating unit (124, 125, 126) includes an mho relay element.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP29196798 | 1998-10-14 | ||
JP29196798A JP3790053B2 (en) | 1998-10-14 | 1998-10-14 | Distance relay |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0994548A2 EP0994548A2 (en) | 2000-04-19 |
EP0994548A3 EP0994548A3 (en) | 2002-04-24 |
EP0994548B1 true EP0994548B1 (en) | 2007-01-17 |
Family
ID=17775793
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99118901A Expired - Lifetime EP0994548B1 (en) | 1998-10-14 | 1999-09-24 | Distance relay |
Country Status (6)
Country | Link |
---|---|
US (1) | US6459960B1 (en) |
EP (1) | EP0994548B1 (en) |
JP (1) | JP3790053B2 (en) |
KR (1) | KR100317979B1 (en) |
CN (1) | CN1086853C (en) |
DE (1) | DE69934854T2 (en) |
Families Citing this family (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3456952B2 (en) * | 2000-06-28 | 2003-10-14 | 株式会社東芝 | Digital type distance relay |
JP2003070151A (en) * | 2001-08-27 | 2003-03-07 | Toshiba Corp | Protective relay |
DE10164525A1 (en) * | 2001-12-18 | 2003-07-17 | Siemens Ag | Distance protection method and distance protection device |
JP3830824B2 (en) * | 2002-01-28 | 2006-10-11 | 株式会社東芝 | Digital directional relay |
JP4020304B2 (en) * | 2002-08-09 | 2007-12-12 | 株式会社東芝 | Ground fault direction relay and ground fault direction relay device |
GB2392029A (en) * | 2002-08-16 | 2004-02-18 | Jeffery William Rodbard | Phase failure relay for detecting multiple faults |
EP2084798B1 (en) | 2006-10-18 | 2010-03-24 | ABB Technology Ltd | Load compensation in distance protection of a three-phase power transmission line |
US8675327B2 (en) * | 2007-03-30 | 2014-03-18 | General Electric Company | Fast impedance protection technique immune to dynamic errors of capacitive voltage transformers |
JP5063171B2 (en) * | 2007-04-17 | 2012-10-31 | 三菱電機株式会社 | Distance relay device |
CN102131494B (en) * | 2008-04-23 | 2016-05-11 | 巴斯夫欧洲公司 | Hydrophobic benefit agent is waited until sending keratinous substrates from bath agent |
JP5383095B2 (en) * | 2008-06-05 | 2014-01-08 | 中国電力株式会社 | Relay operation determination device, relay operation determination method, and relay operation determination program |
CN102119474B (en) * | 2008-07-07 | 2014-01-22 | Abb研究有限公司 | Fast power swing unblocking method and apparatus for distance protection in power system |
JP5438935B2 (en) * | 2008-08-29 | 2014-03-12 | 株式会社東芝 | Short-circuit distance relay |
KR101231705B1 (en) | 2011-03-03 | 2013-02-08 | 한전케이디엔주식회사 | Validity verification method for setting determination of distance relay setting |
CN102253309B (en) * | 2011-04-29 | 2013-07-31 | 上海磁浮交通发展有限公司 | Method for determining multipoint earth faults of long stator according to line voltage |
US9130364B1 (en) * | 2012-12-18 | 2015-09-08 | Becker Mining America, Inc. | Electrical hot circuit indicator |
RU2538091C2 (en) * | 2013-02-12 | 2015-01-10 | Ян Лейбович Верховский | Method of protection of long rural power transmitting lines lep-0,4 against short circuits |
JP2014217106A (en) * | 2013-04-23 | 2014-11-17 | 三菱電機株式会社 | Distance relay device |
CN103296645B (en) * | 2013-05-19 | 2016-08-03 | 国家电网公司 | Distributed constant is utilized to realize line inter-phase fault distance protection method |
CN103296646B (en) * | 2013-05-19 | 2016-04-06 | 国家电网公司 | Distributed constant is utilized to realize line single-phase earth fault distance protection method |
CN103595022B (en) * | 2013-12-03 | 2017-11-28 | 国家电网公司 | The relay protection and control method of 500kV electric substations 35kV house transformer current-limiting reactors |
CN103762572A (en) * | 2014-02-18 | 2014-04-30 | 国家电网公司 | Electric transmission line power frequency deviation component current differential protection method based on direction coefficient |
CN104167721A (en) * | 2014-08-29 | 2014-11-26 | 东南大学 | Relay protection method based on ultra-high voltage alternating-current long lines |
EP3723224B1 (en) * | 2019-04-08 | 2023-08-23 | Hitachi Energy Switzerland AG | Time domain distance protection based on polarity comparison for power transmission lines |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55125025A (en) * | 1979-03-19 | 1980-09-26 | Tokyo Electric Power Co | Digital distance relay |
US4329727A (en) * | 1980-07-16 | 1982-05-11 | General Electric Company | Directional power distance relay |
JPS5854825A (en) * | 1981-09-29 | 1983-03-31 | 株式会社東芝 | Protective relay unit |
US4405966A (en) * | 1981-10-07 | 1983-09-20 | General Electric Company | System for providing protection for a high voltage transmission line |
US4433353A (en) * | 1982-07-29 | 1984-02-21 | General Electric Company | Positive sequence undervoltage distance relay |
JPS6039312A (en) | 1983-08-10 | 1985-03-01 | 株式会社東芝 | Protective relaying device |
JPH0754709B2 (en) | 1989-06-16 | 1995-06-07 | 大阪瓦斯株式会社 | Fuel cell |
US5140492A (en) * | 1990-04-11 | 1992-08-18 | Schweitzer Engineering Laboratories, Inc. | Distance relay using a polarizing voltage |
JP3447402B2 (en) * | 1994-11-30 | 2003-09-16 | 株式会社東芝 | Digital distance relay |
DE19605025C2 (en) * | 1996-01-31 | 2003-06-18 | Siemens Ag | Distance protection method |
-
1998
- 1998-10-14 JP JP29196798A patent/JP3790053B2/en not_active Expired - Fee Related
-
1999
- 1999-08-24 US US09/379,922 patent/US6459960B1/en not_active Expired - Lifetime
- 1999-09-24 EP EP99118901A patent/EP0994548B1/en not_active Expired - Lifetime
- 1999-09-24 DE DE69934854T patent/DE69934854T2/en not_active Expired - Fee Related
- 1999-10-07 KR KR1019990043200A patent/KR100317979B1/en not_active IP Right Cessation
- 1999-10-14 CN CN99121922A patent/CN1086853C/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
"Backup protective relay systems", ELECTRICAL JOINT RESEARCH, vol. 37, no. 1, 5 June 1981 (1981-06-05), pages 41 * |
Also Published As
Publication number | Publication date |
---|---|
EP0994548A2 (en) | 2000-04-19 |
CN1086853C (en) | 2002-06-26 |
EP0994548A3 (en) | 2002-04-24 |
KR20000028893A (en) | 2000-05-25 |
JP2000125462A (en) | 2000-04-28 |
CN1250964A (en) | 2000-04-19 |
DE69934854T2 (en) | 2007-10-18 |
DE69934854D1 (en) | 2007-03-08 |
KR100317979B1 (en) | 2001-12-22 |
JP3790053B2 (en) | 2006-06-28 |
US6459960B1 (en) | 2002-10-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0994548B1 (en) | Distance relay | |
US6442010B1 (en) | Differential protective relay for electrical buses with improved immunity to saturation of current transformers | |
US6341055B1 (en) | Restraint-type differential relay | |
US7906970B2 (en) | Current differential protection relays | |
CA2735726C (en) | Short-circuit distance relay | |
US20040021995A1 (en) | Ground fault detection system for ungrounded power systems | |
US20060152866A1 (en) | System for maintaining fault-type selection during an out-of-step condition | |
US4686601A (en) | Ground distance relay for AC power transmission line protection | |
EP0316204B1 (en) | Protective relay | |
US6661630B1 (en) | Distance relay for protection of transmission line having minimized reactance effect | |
KR102021813B1 (en) | Ground fault overvoltage relay | |
JP2004080839A (en) | Ground direction relay and ground direction relay device | |
US5808845A (en) | System for preventing sympathetic tripping in a power system | |
US8395871B2 (en) | Device and method for detecting faulted phases in a multi-phase electrical network | |
Kasztenny | Impact of transformer inrush currents on sensitive protection functions | |
JP2971329B2 (en) | Bus protection relay | |
JP2781102B2 (en) | Bus protection relay | |
JP3011420B2 (en) | Digital bus protection relay | |
JPH11191922A (en) | Digital ground distance relaying device | |
JP3430327B2 (en) | Fault location starter | |
Al-Fakhri | A unique transformer protection which eliminates over-voltage, over-fluxing, and CT saturation protection | |
JP2607483B2 (en) | Ground fault directional relay | |
JP2002027661A (en) | Leakage detection/protection method and apparatus for commonly grounded circuit | |
JPH0517771B2 (en) |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19990924 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE Kind code of ref document: A2 Designated state(s): CH DE FR GB LI SE |
|
AX | Request for extension of the european patent |
Free format text: AL;LT;LV;MK;RO;SI |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
|
AX | Request for extension of the european patent |
Free format text: AL;LT;LV;MK;RO;SI |
|
AKX | Designation fees paid |
Free format text: CH DE FR GB LI SE |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): CH DE FR GB LI SE |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: SE Ref legal event code: TRGR |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
REF | Corresponds to: |
Ref document number: 69934854 Country of ref document: DE Date of ref document: 20070308 Kind code of ref document: P |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: NV Representative=s name: E. BLUM & CO. AG PATENT- UND MARKENANWAELTE VSP |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed |
Effective date: 20071018 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20080915 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20081002 Year of fee payment: 10 Ref country code: CH Payment date: 20081016 Year of fee payment: 10 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20100531 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20090930 Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20100401 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20090930 Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20090930 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20110921 Year of fee payment: 13 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20120924 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20120924 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 20140911 Year of fee payment: 16 |
|
REG | Reference to a national code |
Ref country code: SE Ref legal event code: EUG |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150925 |